Baffle A device used to direct sound in a particular direction. Billet Cylinder Head Any component that has been machined from a solid billet. The billet will have been rolled or forged, not cast. The billet is then machined into a component. Breakout Used only in handicap racing, "Breakout" refers to a competitor running quicker than their "dial-in" (i.e. ran a time quicker/ lower than their prediction). Unless the opponent commits a more serious foul (e.g., red-lights, crosses the centreline, or fails a post-race inspection), the driver who breaks out loses. If both competitors breakout, the one who runs closest to his or her dial is the winner. Burnout Spinning the rear tyres in water to heat and clean them prior to a run for better traction. A burnout precedes every run. Butt Weld The “butting” together of two pieces of material for welding, without external reinforcement, overlap or “sleeving”. Bye Run A single or solo pass produced by uneven numbers in the elimination process. Car A four wheeled vehicle used to transport a person, powered by an internal combustion engine or electric motor. Christmas Tree Also called The Tree, it is the noticeable electronic starting device between the lanes on the starting line. It displays a calibrated-light countdown for each driver. Chromoly or CroMo Abbreviations for Chromium Molybdenum Steel (CM4130). Clutch Can The bell-shaped housing, or Bellhousing, used to encase the clutch and Flywheel. Clutch Lockup The progression of clutch-disc engagement controlled and/or activated by mechanical, electronic or pneumatic means. Refer Definitions, “Lock-up clutch”. Clutchless Gearbox Any manual transmission for which the disengagement of a clutch is not intended when changing between ratios. Clutch Required In relation to manual type transmissions using spur gears, means the use of the clutch is intended when shifts are made, and split selection sliders are not permitted. Computer Any electrical and/or electronic device that activates or modifies any function of, or in any way effects the operation of the vehicle based on measurement, sensing, processing, etc., of any data related to the performance of the vehicle (a reactive device).